The strange-face illusion is a psychological effect in which a person’s face begins to look distorted, unfamiliar, or frightening during prolonged eye contact in dim light. Research on this phenomenon shows that under unusual viewing conditions, normal face perception can become unstable and produce vivid distortions.[1][2] This effect has been studied by Italian psychologist Giovanni B. Caputo. In these studies, participants either looked at their own reflection or stared into another person’s eyes for several minutes in low light, and many reported seeing strange changes in the face before them.[2][1] ## How the illusion works A typical version of the experiment is simple. Two people sit facing each other, usually about one meter apart, in a dimly lit room and silently maintain eye contact for several minutes.[3][2] After some time, participants may begin to notice unusual visual changes. The face in front of them can appear warped, older, unfamiliar, unreal, or transformed into a di...